Immune recovery was retrospectively analyzed in a cohort of 41 patients with acute leukemia, myelodysplastic syndrome and nonmalignant diseases, who received αβ T- and B-cell-depleted allografts from ...haploidentical family donors. Conditioning regimens consisted of fludarabine or clofarabine, thiotepa, melphalan and serotherapy with OKT3 or ATG-Fresenius. Graft manipulation was carried out with anti-TCRαβ and anti-CD19 Abs and immunomagnetic microbeads. The γδ T cells and natural killer cells remained in the grafts. Primary engraftment occurred in 88%, acute GvHD (aGvHD) grades II and III-IV occurred in 10% and 15%, respectively. Immune recovery data were available in 26 patients and comparable after OKT3 (n=7) or ATG-F (n=19). Median time to reach >100 CD3+ cells/μL, >200 CD19+ cells/μL and >200 CD56+ cells/μL for the whole group was 13, 127 and 12.5 days, respectively. Compared with a historical control group of patients with CD34+ selected grafts, significantly higher cell numbers were found for CD3+ at days +30 and +90 (267 vs 27 and 397 vs 163 cells/μL), for CD3+4+ at day +30 (58 vs 11 cells/μL) and for CD56+ at day +14 (622 vs 27 cells/μL). The clinical impact of this accelerated immune recovery will be evaluated in an ongoing prospective multicenter trial.
We report on posttransplant relapsed pediatric patients with B-precursor acute lymphoblastic leukemia with no further standard of care therapy who were treated with the T-cell engaging ...CD19/CD3-bispecific single-chain antibody construct blinatumomab on a compassionate use basis. Blast load was assessed prior to, during and after blinatumomab cycle using flow cytometry to detect minimal residual disease, quantitative polymerase chain reaction for rearrangements of the immunoglobulin or T-cell receptor genes, and bcr/abl mutation detection in one patient with Philadelphia chromosome-positive acute lymphoblastic leukemia. Blinatumomab was administered as a 4-week continuous intravenous infusion at a dosage of 5 or 15 μg/m(2)/day. Nine patients received a total of 18 cycles. Four patients achieved complete remission after the first cycle of treatment; 2 patients showed a complete remission from the second cycle after previous reduction of blast load by chemotherapy. Three patients did not respond, of whom one patient proceeded to a second cycle without additional chemotherapy and again did not respond. Four patients were successfully retransplanted in molecular remission from haploidentical donors. After a median follow up of 398 days, the probability of hematologic event-free survival is 30%. Major toxicities were grade 3 seizures in one patient and grade 3 cytokine release syndrome in 2 patients. Blinatumomab can induce molecular remission in pediatric patients with posttransplant relapsed B-precursor acute lymphoblastic leukemia and facilitate subsequent allogeneic hematopoietic stem cell transplantation from haploidentical donor with subsequent long-term leukemia-free survival.
Natural killer (NK) cell activity has been shown to have potential activity against Ewing's sarcoma (EWS) especially in tumors with low HLA I expression and high NKG2D expression. Two patients with ...metastatic relapsed and primary metastatic stage IV EWS who had received two courses of high dose chemotherapy with autologous stem cell rescue were transplanted from a haploidentical parental stem cell donor. Patients are alive in ongoing CR for 10.2 and 3.4 years now. Post transplant local second and first relapses were treated successfully in both patients. In vivo IL-2 stimulation not only increased the number and activity of effector cells in one patient but was also associated with severe GvHD. In vitro studies demonstrated high NK cell activity against K562 and relevant activity against EWS cell line A673 post transplant. NK activity was enhanced by cytokine prestimulation as well as by EWS targeting anti-GD2 Ab. Haploidentical hematopoietic stem cell transplantation (HSCT) might contribute to long-term survival by NK cell-mediated effect exerted by donor-derived NK cells. Local tumor recurrence was manageable in both high-risk patients indicating systemic immune control preventing subsequent metastasizing. The efficacy of haploidentical HSCT, cytokine application and tumor targeting antibodies for the use of Ab-dependent cellular cytotoxicity needs evaluation in clinical trials.
Natural killer cells have been demonstrated to exert remarkable graft-versus-leukemia effects after haploidentical transplantation. Acquisition of both, inhibiting and activating, receptors on ...developing natural killer cells is an important step in their functional maturation. Here, we report on the reconstitution of natural killer receptors after haploidentical transplantation of T-and B-cell (CD3/CD19) depleted grafts with co-transfusion of natural killer cells in children and its influence on natural killer cell activity and clinical outcome.
We analyzed reconstitution patterns of natural killer receptors at different time intervals after haploidentical transplantation by multi-color flow cytometry. Natural killer cell activity and antibody-dependent cellular cytotoxicity was tested against cell lines and leukemic blasts in vitro. Survival was analyzed using Kaplan-Meier estimates.
Recovery of CD56(+)/CD16(+) cells was fast with high cytolytic activity against K562 and strong antibody-dependent cellular cytotoxicity activity against neuroblastoma and leukemic blasts as early as day 14 posttransplant. KIR reconstitution showed a predominance of KIR negative natural killer cells early after transplantation and an early reconstitution of CD158b compared to CD158a and CD158e. These differences were independent of presence or absence of the corresponding KIR ligands in donors or recipients. This reconstitution pattern was associated with a higher relapse probability of patients homozygous for HLA-C1-alleles compared to patients homozygous or even heterozygous for HLA-C2-alleles.
Our results indicate a fast recovery of functional and alloreactive natural killer cells with a constant KIR pattern after haploidentical transplantation with T- and B-cell depleted grafts. Moreover, these natural killer cells can mediate antibody-dependent cellular cytotoxicity and therefore may allow for an early use of antibodies against residual malignant cells.
Relapse after allo-SCT in patients with acute leukaemia remains a major problem. A beneficial impact of alloreactive natural killer (NK) cells has been reported for myeloid malignancies, but has been ...questionable for B-lineage ALL. We analysed lysis of primary paediatric precursor-B-ALL blasts by 285 NK cell clones to investigate whether HLA class I expression on the blasts and phenotypic killer cell Ig-like receptor (KIR) expression on NK cells affect the lytic activity against ALL blasts. Precursor-B-ALL blasts with low HLA-I expression were lysed by a majority (79%) of NK cell clones, whereas those with high HLA-I expression showed low susceptibility to NK clones independent of their KIR expression patterns. NK cell activity against susceptible blasts was regulated by differential surface expression of the three major KIRs (CD158a, CD158b, CD158e). NK clones with none of these three KIRs or a single KIR that recognized no ligand, were not inhibited by the targets and exerted higher lysis (P = <0.0005) in comparison to NK clones expressing KIRs with a ligand on the ALL blasts. In conclusion, the quantity of HLA-I expression on precursor-B-ALL blast regulates overall NK cell susceptibility; in case of reduced HLA expression, differential surface expression of KIRs affects NK cell alloreactivity against those blasts.
Immune recovery was retrospectively analyzed in a cohort of 41 patients with acute leukemia, myelodysplastic syndrome and nonmalignant diseases, who received alpha beta T- and B-cell-depleted ...allografts from haploidentical family donors. Conditioning regimens consisted of fludarabine or clofarabine, thiotepa, melphalan and serotherapy with OKT3 or ATG-Fresenius. Graft manipulation was carried out with anti-TCR alpha beta and anti-CD19 Abs and immunomagnetic microbeads. The gamma delta T cells and natural killer cells remained in the grafts. Primary engraftment occurred in 88%, acute GvHD (aGvHD) grades II and III-IV occurred in 10% and 15%, respectively. Immune recovery data were available in 26 patients and comparable after OKT3 (n=7) or ATG-F (n=19). Median time to reach >100 CD3+ cells/ mu L, >200 CD19+ cells/ mu L and >200 CD56+ cells/ mu L for the whole group was 13, 127 and 12.5 days, respectively. Compared with a historical control group of patients with CD34+ selected grafts, significantly higher cell numbers were found for CD3+ at days +30 and +90 (267 vs 27 and 397 vs 163 cells/ mu L), for CD3+4+ at day +30 (58 vs 11 cells/ mu L) and for CD56+ at day +14 (622 vs 27 cells/ mu L). The clinical impact of this accelerated immune recovery will be evaluated in an ongoing prospective multicenter trial.
Immune recovery was retrospectively analyzed in a cohort of 41 patients with acute leukemia, myelodysplastic syndrome and nonmalignant diseases, who received alphabeta T- and B-cell-depleted ...allografts from haploidentical family donors. Conditioning regimens consisted of fludarabine or clofarabine, thiotepa, melphalan and serotherapy with OKT3 or ATG-Fresenius. Graft manipulation was carried out with anti-TCRalphabeta and anti-CD19 Abs and immunomagnetic microbeads. The gammadelta T cells and natural killer cells remained in the grafts. Primary engraftment occurred in 88%, acute GvHD (aGvHD) grades II and III-IV occurred in 10% and 15%, respectively. Immune recovery data were available in 26 patients and comparable after OKT3 (n = 7) or ATG-F (n = 19). Median time to reach > 100 CD3+ cells/microL, > 200 CD19+ cells/microL and > 200 CD56+ cells/microL for the whole group was 13, 127 and 12.5 days, respectively. Compared with a historical control group of patients with CD34+ selected grafts, significantly higher cell numbers were found for CD3+ at days +30 and +90 (267 vs 27 and 397 vs 163 cells/microL), for CD3+4+ at day +30 (58 vs 11 cells/microL) and for CD56+ at day +14 (622 vs 27 cells/microL). The clinical impact of this accelerated immune recovery will be evaluated in an ongoing prospective multicenter trial. Bone Marrow Transplantation (2015) 50, S6-S10; doi: 10.1038/bmt.2015.87
Zusammenfassung
Im Rahmen aktueller Therapieoptimierungsstudien, die z. T. eine Hochdosischemotherapie mit autologem Stammzellsupport (autologe Stammzelltransplantation) einschließen, können ...pädiatrische Patienten mit soliden Tumoren häufig erfolgreich behandelt werden. Metastasierte Rezidive und bestimmte Höchstrisikogruppen hingegen können meist noch nicht kurativ angegangen werden. Eventuell könnten diese Patienten von einer allogenen Transplantation und dem damit verbundenen, immunologisch vermittelten Antitumoreffekt profitieren. Obwohl frühere, nicht randomisierte Vergleichsstudien mit stark limitierter Patientenzahl keinen Vorteil für die allogene Transplantation ergaben, existieren genügend experimentelle und klinische Hinweise auf einen Graft-versus-Tumor(GvT)-Effekt, um eine neuerliche Evaluation in aktuell laufenden pädiatrischen Studien mit deutlich reduzierter transplantationsassoziierter Toxizität zu rechtfertigen. Von der GPOH (Gesellschaft für pädiatrische Onkologie und Hämatologie) wird v. a. die Stammzelltransplantation von einem haploidentischen Familienspender mit nachfolgender Immuntherapie untersucht.
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